Door check



S. P. MORGEN April 4, 1939,

A 36 5 dp/lyvEN'roR. fgur argan.

ATTORNEYS.

Patented Apr. 4, 1939 UNITED STATES PATENT OFFlCE DOOR CHECK Application June 15, 1938, Serial No. 213,750

1 Claim. -(Cl. 16-59) The present invention relates to door checks, and has special reference to door checks of the type which have a checking action both during opening and closing of the door, and in which the 5 checking action is accomplished by means of a liquid within the check cylinder.

The principal object of the invention is to pro- Vide a device of this character which is simple in construction, and capable of operating smoothly and uniformly during both the opening and the closing of the door.

The preferred form of the invention is illustrated, by way of example, in the accompanying drawing, in which:

Figure 1 is a vertical sectional View, partly in elevation, of the improved door check, the upper portion of the check being broken away to save space;

Fig. 2 is a longitudinal sectional plan View of the door-check, the section being taken through the piston chamber; and

Fig. 3 is a detail sectional view taken on the line 3 3 of Fig. 1.

The door check illustrated in the drawing is provided with a casing having a piston chamber or cylinder 2, one end of which is closed by a removable cap 4 screw-threaded thereon, and the other end E of which is formed integrally with the piston chamber. Within the cylinder there 30 is a piston 8 having heads lll and I2. The piston is adapted to be reciprocated through racks I4 which are adapted to be alternately engaged by a segmental pinion I6 formed on a shaft I8 which is adapted to be turned in one direction by a door- 3 closing spring 20 enclosed within a chamber 22 at the top of the piston cylinder.

The end 5 of the cylinder is provided with a by-pass 2l having an inlet port 23 and a by-pass 24 having an inlet port 25. The ports 23 and 25 40 are adapted to be respectively controlled through valves 26 and 28. By-passes 2| and 2d and the valves 26 and 28 may be and preferably are of the arrangement and construction described and claimed in the patent to W. F. Moore, No.

45 1,929,251, dated October 3, 1933.

Each of the piston heads lll and IZ is provided with a ball check valve 30, the check valve in the head l2 being removably mounted in a block or plug 32 screw-threadedinto an aperture in the 50 head. The head IZ is also provided with a by-pass or orice 34 which extends through the plug 32.

In the illustrated construction, the inner side of the bottom wall of the piston cylinder is provided with release cuts or recesses 36 at opposite sides of the lower end of the shaft I8. The bottom wall of each recess 36 is inclined upwardly and outwardly with its outer end substantially flush with the cylindrical wall of the piston chamber. 'Ihe side walls of each recess 36 converge toward their outer ends.

In the drawing the piston is shown in the position which it assumes when the door is wide open. During the first part of the door closing movement of the piston the liquid is free to pass through one of the release cuts or recesses 36 and 10 beneath the associated piston head, but the ow of the liquid through this recess is gradually cut off until the forward end of the piston head passes the forward end of the recess, whereby further passage through this recess is entirely cut off.

Also, during the first part of the door-closing movement of the piston, the liquid in advance of the piston is permitted to pass more or less freely out through the ports 23 and 25 so that the door may close rapidly, but when the door 20 approaches closed position, the piston closes the port whereupon all the liquid must pass out through the port 23 so that the door may be caused to nally close slowly.

During the movement of the piston in the op- 25 posite direction which occursY during the opening movement of the door, the check valve in the head l2 of the piston closes so that the liquid in advance of this head of the piston can pass only through the orice 34 and one of the re- 30 lease recesses 36. As the piston head passes over this recess 36 the ow therethrough is gradually cut olf, thus gradually increasing the resistance of the liquid until the outer end of the head I2 passes the outer end of the recess, whereupon the flow through this recess is entirely cut olf and all further flow of the liquid must be through the oriiice 34. Such cutting off of said recess 33 occurs as the door approaches its wide open position.

Thus during the opening of the door the fluid rst will offer a minimum resistance and then the resistance will be gradually increased until the outer end of the head completely cuts off the recess 35, thereby insuring relatively slow nal opening of the door.

As will be evident to those skilled in the art my invention permits various modifications without departing from the spirit thereof or the scope of the appended claim.

What I claim is:

In a door-check of the class described, a piston chamber, a double-headed piston within the chamber, a check valve in each piston head whereby during the movement of the piston in either direction the ow of fluid through the advancing head is cut oi and fluid is permitted to pass through the other head, the piston head that advances during the opening of the door having a by-pass therein, said chamber having a longitudinally extending recess in the inner side of its Wall extending from near the center of the chamber toward the end of the chamber opposite the last-mentioned piston head, said recess having its cross-sectional area gradually restiicted from its inner end to its outer end whereby during the rst part of the door-opening movement of said piston head the uid is free to flow through said recess, the flow being gradually cut off as the head passes over said recess until it is finally cut oi upon said head of the piston passing the outer end of said recess.

SIGURD P. MORGEN. 

